Federal prosecutors brought criminal insider-trading charges against Mr. London, who they said reaped more than $50,000 in cash and gifts for providing advance notice of clients’ earnings releases or merger plans. The scheme involved tips on five public companies, wads of $100 bills and a sting operation in which agents bundled bags of cash and recorded Mr. London accepting them.

He told the Journal last June that he had been driven by wanting to help out Mr. Shaw, whose jewelry business was struggling. After receiving payments from Mr. Shaw, he said in that interview, “I’d feel like I just robbed somebody and I’d feel totally guilty.” But “unfortunately those feelings weren’t enough to keep me from doing it.” He called it a “slippery slope.”

By the 14th time Mr. London engaged in the activity, “it wasn’t inadvertent,” the judge said. But the judge took into account Mr. London’s past actions as a 30-year employee with no prior criminal record. “I do think this was extremely out-of-the-ordinary conduct,” Judge Wu said.